Sovereign Cloud Stack

One platform — standardized, built and operated by many.

SCS Release 6 published

Sovereign Cloud Stack March 20, 2024

Sovereign full-stack cloud solution

Sovereign Cloud Stack publishes Release 6

Berlin, 20.03.2024: The Sovereign Cloud Stack project publishes its sixth release.

Release 6 focuses on the SCS Kubernetes Distribution Cluster Stacks, which can be rolled out directly on the IaaS reference implementation via the Cluster Stack Operator. The reference implementation now also includes the Observability Platform and enhanced Identity and Access Management. The collaboration with ALASCA e.V. has resulted in enhanced speed and scope in the development of comprehensive open standards, in line with the requirements of the German Administrative Cloud Strategy. Overall, SCS Release 6 offers an easy-to-operate, sovereign full-stack cloud solution.

SCS provides all the cloud technology foundations for realizing digital sovereignty and implementing open source strategies. Many users of cloud services from the public sector, but also from the private sector and science, expect “cloud” to be container-based technology that can ideally be hosted and operated in a digitally sovereign manner. This is now even easier to achieve: SCS offers a digitally sovereign, secure, complete, standardized open source container layer as the basis for all containerized applications.

SCS Full Stack: Unification of IaaS and KaaS reference implementation completed

Release 6 introduces the Cluster Stacks, the second version of the Kubernetes as a Service reference implementation from SCS, which can now be seamlessly rolled out on the Infrastructure as a Service layer from SCS thanks to the implementation of the Cluster Stack Operator. The cluster stacks are fully implemented with Kubernetes on-board tools such as operators and thus replace the old implementation, which still integrated and automated the cluster API with the help of scripts. The cluster stacks are complemented with identity and access management and an observability platform which ensure that the stack is more secure and easier to operate.

SCS thus offers an integrated full-stack cloud solution that combines a scalable, secure cloud infrastructure and a container platform that can be developed and tested according to the latest requirements. SCS continues to offer a fully open standards-based software solution developed openly by many contributors, which can be influenced and shaped by operators and users and offers a high degree of transparency - the perfect basis for driving digitally sovereign innovation at all levels in Germany and Europe.

Cooperation on standardization

In the fall of last year, the cooperation between the SCS project and ALASCA e.V. was intensified once again. The further development of open standards, as called for in the German Administrative Cloud Strategy, for example, is at the forefront of this cooperation. Release 6 shows how fruitful this cooperation already is, with examples of SCS standards including

For the operators of SCS cloud environments, it is an advantage that the implementation of the standards and the resulting certification provides them with a simple quality criterion (in the best sense of the word) that relates not only to interoperability and openness, but also to robustness, security and up-to-dateness. In this way, they not only assure their customers of the quality of their offering, but also themselves. Of course, interoperability is of particular interest to users: they can roll out their workloads on the clouds of multiple operators without any major surprises, which gives them a high degree of flexibility and in some cases may be a prerequisite to open up an alternative to the large hyperscalers (AWS, Google, Azure).

Simple operation of cloud environments

Overall, Release 6 makes it clear that SCS cloud infrastructure can be operated efficiently: this was and is one of the central value propositions of the SCS project, alongside control and simple provisioning for end users. The operating tools have been consistently expanded to simplify everyday work steps for the operating staff. The continuous standardization of further aspects and especially the implementation of the standards by providers who do not use the IaaS reference implementation underline the relevance of the standardization work. With the latest developments and the release of Cluster Stacks for OpenStack, deployment environments for Kubernetes clusters are easier and more efficient to manage.

In the reference environment, a standardized Kubernetes environment is now also available at the infrastructure level, into which operators can integrate their own tools (e.g. for billing or capacity management); with the Identity and Access Management (IAM) from the SCS reference implementation, a supplied service also makes use of this integration option. The expansion of the SCS documentation also contributes directly to the efficient operation of SCS cloud environments; examples, instructions and links to the repositories make the structure of SCS clear, comprehensible and efficient.

About the Sovereign Cloud Stack Project

SCS has been funded by the German Federal Ministry of Economics and Climate Protection (BMWK) since July 2021 and is run by the Open Source Business Alliance - Bundesverband für digitale Souveränität e.V.. A growing, international ecosystem of now over 25 companies contributes to the success of the Sovereign Cloud Stack with over 50 software developers. Together, open standards for a modern, federatable open source cloud and container platform are defined and implemented in an open development process using proven open source components. At the same time, operational knowledge and practice is being made transparently available to minimize the difficulty of delivering high-quality and secure cloud services. Already six providers are using SCS technology productively to operate truly sovereign and GDPR-compliant public cloud offerings. Additional SCS-based cloud infrastructure (public and private clouds) is under construction. SCS also contributes to Gaia-X and provides the development platform for the Gaia-X Federation Services / Cross-Federation Service Components (GXFS/XFSC).

About the Open Source Business Alliance (OSB Alliance) e.V.

The Open Source Business Alliance (OSB Alliance) is the association of the open source industry in Germany. It represents over 200 member companies that generate more than EUR 126 billion annually in total. Together with scientific institutions and user organizations, it works to sustainably anchor the central importance of open source software and open standards for a successful digital transformation in the public awareness. In addition, innovations in the field of open source are to be promoted. The goal of the OSB Alliance is to establish open source as a standard in public procure­ment and in research and business development. After all, open source and open standards are compelling foundations for digital sovereignty, innovation capability and security in the digital transformation and thus the answer to one of the greatest challenges of our time.

Sovereign Cloud Stack:

Technical Documentation SCS:

SCS Repositories (github):

Release notes:

SCS’s notion of digital sovereignty: and

Release Blog Posts: and

Copyright picture: Engin Akyurd


OSB Alliance – Bundesverband für digitale Souveränität e.V., Pariser Platz 6a, 10117 Berlin, Germany